Django-REST Framework Object Level Permissions and User Level Permissions

from django.utils.translation import ugettext_lazy as _
from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin
 
class User(AbstractBaseUser, PermissionsMixin):
    USER_TYPES = (
       ("Author", "Author"),
       ("Reader", "Reader"),
       ("Publisher", "Publisher")
    )
    username = models.CharField(max_length=100, unique=True)
    first_name = models.CharField(_("first name"), max_length=30, blank=True, null=True)
    last_name = models.CharField(_("last name"), max_length=30, blank=True, null=True)
    email = models.EmailField(_("email address"), unique=True)
    is_staff = models.BooleanField(_("staff status"), default=False)
    is_active = models.BooleanField(_("active status"), default=True)
    user_type = models.CharField(choices=USER_TYPES)
    
    def __str__(self):
       return self.email


class Book(models.Model):
    READ_OPTIONS = (
      ('YES', 'YES'),
      ('NO', 'NO')
    )
    name = models.CharField(max_length=300)
    pages = models.IntegerField()
    price = models.DecimalField(max_digits=10, decimal_places=2)
    rating = models.FloatField()
    is_allowed_to_read = models.CharField(choices=READ_OPTIONS)

    def __str__(self):
      return self.name

from rest_framework.permissions import BasePermission

class IsAllowedToWrite(BasePermission):
    
    def has_permission(self, request, view):
        return request.user.user_type == "Author"


class IsAllowedToRead(BasePermission):
    
    def has_object_permission(self, request, view, obj):
        return obj.is_allowed_to_read == "YES"

from rest_framework import generics
from app.permissions import IsAllowedToWrite, IsAllowedToRead
from app.serializers import WriteBookSerializer, 


class WriteBookView(generics.CreateAPIView):
  
    serializer_class = WriteBookSerializer
    permission_classes = (IsAllowedToWrite,)


class ReadBookView(generics.RetrieveAPIView):
  
    serializer_class = ReadBookSerializer
    permission_classes = (IsAllowedToWrite,)